I previously purchased Charlotte's 40D Field Guide and found it to be an excellent adjunct to the Canon owners manual. I have often wondered why manufactures can not write lucid, easy to understand directions. Charlotte has remedied this by turning out another fine guide in the 7D edition. I received it from Amazon Dec. 12th and quickly read thru it, and now I am going back and studying it in depth, particularly the sections pertaining to the autofocus system. Charlotte not only tells you what the various 7D features are, but where they are useful, using real life illustrations from her professional work, and then how to implement them step by easy step.
The 7D autofocus system has to be one of the best available, if not indeed the best. But it is full featured and to use it to maximum advantage one should have a complete understanding of it's capabilities and functionality. Charlotte does a fine job explaining both. The 7D was unfairly maligned on the web forums by early adopters because they did not study the autofocus system before attempting to capture images and be the first to get them online. I have not had one problem with the 7D, and the 18-135 kit lens is one of the best I have used, and I have some fine lenses including Canon "L".
Charlotte's 7D book will probably be best appreciated by those who have a basic understanding of the interplay between ISO setting, F stop, and shutter speed for obtaining proper exposures. I am not looking "down my nose" at those who are learning, but the 7D is very fully featured and I do not think of it as an "entry" level camera. I have a lot of experience, being trained by the U.S. Army over fifty years ago as a Still Picture Photographer, but I find much useful information in my Charlotte Lowrie Field Guides and I highly recommend them. In closing, I have frequently utilized the Picture Style recommendation by Charlotte for the 40D, and I used her 7D Style recently for a "Santa Claus" event I did for a local Children's Specialty Shop. I shot in large raw and medium jpg and the jpg results were so outstanding, I did not have to do any raw processing, only cropping and then uploading to Mpix for printing. The workflow time savings from her Style recommendation alone was worth the price of the book.